1. Field of the Invention
This invention relates generally to Logical Transform Processors, and more specifically to a Logical Transform Processor that performs a plurality of related transformations simultaneously.
2. Description of the Prior Art
An unprocessed image, derived from objects on the surface of the earth by a satellite camera, from objects in a histological section by a digital microscope or derived in any other manner, is often enhanced by computer processing. The enhancement may be used for clarification where, for example, a computer processor determines, from a signal representation of the unprocessed image, portions thereof that are relevant. Based upon the determination, the processor provides a signal representation of the relevant portions.
The unprocessed image is comprised of a multiplicity o least resolvable elements, known as pixels. A pixel is either black or white. A signal representation of the pixel is usually either a logic "1" signal or a logic "0" signal when the pixel is either black or white, respectively. Accordingly, the signal representation of the unprocessed image is comprised of signals representative of all of the pixels of the unprocessed image.
The processing of the pixel is usually equivalent to comparing an array formed by the pixel and pixels proximal thereto (referred to as neighbors hereinafter) to all possible arrays. Based upon the comparison, the pixel is, for example, either included as a black element or a white element of a processed image.
One type of array, known as a square tessellation, includes the pixel at the center of an imaginary square. A neighborhood of the square tessellation is comprised of pixels respectively located at the corners of the square and at the midpoints of lines comprising the square.
Another type of array, known as a hexagonal tessellation, includes the pixel at the center of an imaginary hexagon. A neighborhood of the hexagonal tessellation is comprised of pixels at the corners of the hexagon.
The processing of image fields has been described in detail in U.S. Pat. No. 4,060,713 by M. J. E. Golay.
The processor may easily serially process the signal representation of the unprocessed image. Signals representative of the pixel and its neighbors are fetched from a memory element of the processor. The fetched signals are compared to groups of signals respectively representative of all possible combinations of the pixel and its neighbors. Based upon the comparison, the signal representative of the pixel may be altered, whereby the pixel is processed. After the pixel is processed, a signal representation of the processed pixel and its neighbors are returned to the memory for storage.
Hence, there is a fetch, comparison and storage needed for each pixel of the unprocessed image. It should be appreciated that an unprocessed television image typically is a 512 by 512 array of pixels. Accordingly, the serial processing of the unprocessed television image consumes a large amount of computation time.
The processor usually includes a minicomputer which utilizes a sixteen bit word. In other words, the minicomputer can simultaneously provide sixteen signals respectively representative of sixteen pixels. Heretofore, the signals representative of the sixteen pixels could not be readily processed when the pixel is included in one of several possible tessellations. That is to say, it is difficult to program the processor to readily process one image that includes, for example, pixels in the square tessellation and then another image that includes pixels in the hexagonal tessellation.